29
O
UT OF CAL RANGE FUNCTION
The instrument has a mechanism to prevent taking
measurements in a range where the calibration
does not assure the best results. The message
“
Out of Calibration Range
” is displayed on the
message line in the following situations:
• When the first calibration point is over 0.15 NTU and the reading is under 10 NTU.
• When two point calibration was performed and the reading value is over 40 NTU.
• When a three point calibration was performed and the reading is over 150% of the the third point value.
• When a four point calibration was performed and the reading is over 200% of the the fourth point value.
To take colorimetric measurements follow next
steps:
• Turn the instrument on by pressing ON/OFF.
• Be sure that the correct range is selected
(displayed on the down-right side of the LCD).
Only the
Zero
key is available, indicating that
a zero measurement should be done.
ZEROING THE INSTRUMENT
• Fill a clean, dry cuvette with 10 mL of sample,
up to the mark, taking care to handle the cuvette
by the top.
• Replace the cap.
• Wipe the cuvette thoroughly with a lint-free
cloth to remove any fingerprints, dirt or water
spots.
MEASUREMENT PROCEDURE FOR FREE/TOTAL CHLORINE
When taking Free or Total Chlorine measurements, several basic rules should be followed:
• Never use cuvettes with scratches or cracks because they can cause inaccurate readings.
• Always cap the cuvettes to avoid spillage of the sample into the instrument.
• Always close the lid of the instrument during measurement.
• If is possible use the same cuvette for zero and sample reading.